1. Field of the Invention
The present invention relates to a laminating apparatus wherein a laminate object (object to be laminated) is encapsuled by heat-reactive upper and lower laminate films to perform a laminate treatment by heating and pressurizing the laminate films while sandwiching the laminate object between the laminate films.
2. Related Background Art
In the past, a laminating apparatus wherein appearance and preservation of a sheet-shaped laminated object (referred to as "sheet" hereinafter) are improved by performing a laminate treatment while encapsuling and sealing the sheet between laminate films has been proposed.
FIG. 24 shows an example of such a conventional laminating apparatus.
In FIG. 24, the laminating apparatus 900 includes an upper laminate film roll 901a of an upper heat-reactive laminate film 902a and a lower laminate film roll 901b of a lower laminate film 902b. The laminate films 902a, 902b unwound from the respective laminate film rolls 901a, 901b are wound around respective pressure and heat rollers 903a, 903b which are urged against each other to be laminated and are tensioned by pull rollers 905a, 905b. The pressure and heat rollers 903a, 903b include heaters 906a, 906b for heating the rollers therein, respectively.
From a sheet supply 909 disposed at an upstream side of the paired pressure and heat rollers 903, a sheet 901 is fed to a nip between the pressure and heat rollers 903a, 903b which constitutes a joining point for the upper and lower laminate films 902a, 902b. The sheet 910 is sandwiched by the upper and lower laminate films 902a, 902b and is pressurized and heated by the paired pressure and heat rollers 903, so that it is adhered between the laminate films. Thereafter, the sheet with the laminate films is ejected out of the apparatus by means of the paired pull rollers 905. Trailing ends of the sheet 910 and of the laminate films 902a, 902b are cut by a cutter unit 911 arranged at a downstream side of the paired pull rollers 905.
Above a body 900 of the apparatus, there is arranged an operation portion 913 which has switches 915, 916 for manually setting the feeding speeds of the laminate films 902a, 902b and of the paired pull rollers 905, and the temperature of outer surfaces of the paired pressure and heat rollers 903.
However, in the case where the above conventional laminating apparatus is connected to an image forming system such as a copying machine, when the copying operation is started, if the temperature of the heaters does not reach a predetermined value, it is feared that the laminate films are not adhered to the sheet, thus producing a poor article. Particularly, since the heaters have a low temperature upon initiation of the laminate treatment, many poor articles will be produced until the heaters reach the predetermined temperature. Thus, much sheet and laminate films are consumed, which is wasteful.
Further, conventionally, for example, the control of the temperature of the heaters 906a, 906b was so effected that, after the electric power was turned ON, the temperature was controlled until the melting temperature of the heat-reactive adhesive was obtained, and, thereafter, the temperature was maintained in a constant value during the waiting for the laminate treatment and the laminating operation. Thus, since the temperature of the heaters is maintained in the constant value during the waiting for the laminate treatment and the laminating operation, the temperature of the whole laminating apparatus is considerably increased, so that the elements constituting the apparatus are also heated up, thus reducing the service life of the elements.
Incidentally, if the heater temperature during the waiting time is held to the same temperature as the heater temperature during the laminating operation, the efficiency of the electric power will be worsened.
Further, in the above-mentioned conventional laminating apparatus, pre-heaters sometimes were provided for pre-heating the laminate films 902a, 902b, as well as the heaters 906a, 906b. In this case, however, since the total consumption power of these heaters and pre-heaters had to be set to have a value lower than an acceptable electric power value, the consumption power of the heaters were required to be smaller than the case of no pre-heaters, with the result that it took a long time until the temperature required for the laminate treatment was obtained. Thus, it was feared that the rate of operation was considerably worsened.